All three of Ozil, Mata and Herrera are nearing the ends of their contracts with their current clubs, so could be available on free transfers.

According to Sky Sports, Ozil’s agent hinted earlier this week that talks were progressing well over the Germany international staying at the Emirates Stadium.

However, after a difficult spell in north London it would not be too surprising if he felt tempted to take up an offer from a big club like Barcelona.

Ozil also shone in La Liga earlier in his career, having spent three successful years with Barca’s rivals Real Madrid.

Double United raid by Barcelona?

Mata, meanwhile, is also set to be offered a new deal by United, with the Daily Mirror claiming this week that the Spaniard had turned down other offers to quit the club.

However, that report named Chinese Super League clubs as his main suitors, with an offer from Barcelona likely to be a very different prospect for Mata, who has not started regularly for Jose Mourinho’s side this season.

Finally, Herrera is another player struggling for games right now, but who has always shone when given the chance at Old Trafford.

Barcelona’s penny-pinching may not go down too well with fans as they hope to see their club get back to the top after a difficult summer, though any of those names arriving without transfer fees would have to go down as great business by the Catalans.

That creative midfield role has become something of a problem position for Barcelona in recent times as they eye big names like Coutinho as long-term replacements for legendary playmaker Andres Iniesta.

Ozil, Mata and Herrera may not quite be in that category, but manager Ernesto Valverde will certainly feel they could do a job in the short term at least.